Ricoh Aficio MP driver does not work on OS X

I was recently at an office using a Ricoh Aficio multi-function printer. I downloaded the PPD Installer version 2.2.0.0 (dated 17/09/2014) for OS X 10.11 from the Ricoh Aficio MP 2510/3010/2590/3090 driver page. But no matter what I tried, the printer either could not be found or would print blank or garbled pages...

However, I then deleted the driver by:

1. Deleting the RICOH folder in /Library/Printers and
2. Deleting all files starting with Ricoh in /Library/Printers/PPDs/Contents/Resources

Then I added the printer again, using the standard driver instead. From Settings > Printers & Scanners and add a printer by IP, selecting:

• Protocol: Line Printer Daemon - LPD
• Use: Generic PCL Printer

The printer does not have PS support but the standard Generic PCL driver worked, although it does a terrible job at printing shades in grayscale (uses dithering instead). I have no idea how to fix that...